Cooling apparatus for electric lamps



YSePt- 8, 1942. E. B. NOEL COOLING APPARATUS FOR ELECTRICv LAMPIS 3 Sheets-Sheet 1 Filed AugY 3, 1940 lrvenftor: .Edwafd B. NoeL,

His Aki'or'neg.

8, 1942. E. B, NOEL COOLING APPARATUS FOR ELECTRIC -LAMPS Filed Aug. 3, 1940 3 sheets-shet 2 f I. f v

Inven'toVf Edward B; Noel,

i His Afttornfeg.

sept. s, 1942'. E, B NOEL 2,295,046

COOLING APPARATUS FOR ELECTRIC LAMPS Filed Aug. '3, 1940 "s sheets-#sheet 5 Fig? //0 53 8 D @M HvI- tor neg.

Patented Sept. 8, 1942 Edward B. Noel, Cleveland Heights, Ohio, assignor to General Electric Company, alcorporation of New York Application August 3, 1940, Serial No. 350,471

s claims. (c1. 24o-11.4)

My invention relates in general to high intensity light sources particularly of the small high pressure mercury arc type .such as disclosed and claimed in U.'S. Patent No. 2,094,694, Cornelis Bol et al., issued October, 1937, and assigned to the assignee of the present invention. More particularly, my invention relates to a water cooling arrangement or jacket for such high pressure mercury arc lamps.

High pressure mercury vapor lamps of the type referred to above are provided with relatively small quartz tubesv of the order of 40 mm. or so in length and having an outside diameter of about 6 mm. and a bore of about 2 mm. In lamps of such small volume operating with relatively high power inputs of the order of 800 to 1000 watts and above, it is necessary to effectively cool the lamp in order to dissipate the relatively large energy input within the small bulb volume and prevent softening of the lamp bulb.

It is not suflicient merely to place the lamp in a bath of water. Instead, the water must be passed over the lamp with enough velocity to prevent the formation of steam bubbles on the surface of the quartz bulb. Steam bubbles do not conduct away the heat fast enough to prevent over-heating of the lamp, so that their presence may result in the early failure of the lamp.

'I'he water-cooling arrangements heretofore in use with lamps of the above mentioned type have been more or less unsatisfactory mainly for the reason'that the lamps were not easily replaceable or, in the case of multiple units, a close grouping of the several lamps to thereby form a small compact light source was impossible. In these prior constructions, one or both leads of the lamp were insulated from the cooling water in order to prevent any short-circuiting of the 'current ow through the cooling water with consequent interference to lamp operation. In designs in which both leads were insulated from the water, the leads were sealed in an insulating compound which made it necessary to discard the entire jacket along with the lamp when the latter failed. While considerable simplication and improvement resulted when only one lead to the lamp. was insulated from the cooling water, inasmuch as with such a construction it was possible to make the jacket a permanent part of the installation with only the lamp proper as the renewable element, still such a construction rendered impossible a close grouping of several lamps to form a small and compaci; light source.

One object of my invention is to provide an improved water-cooling arrangement for small electric lamps which is simple in construction and effective in operation.

Another object of my invention is to provide a water-cooling arrangement for small electric lamps which will permit easy replacement of the lamp upon failure of the same.

Still another object of my invention is to provide a'water-cooling arrangement for a plurality of small electric lamps which will permit' a close grouping of the several lamps so as to provide a small and compact light source and which will also permit easy replacement of the individual lamps.

An important feature of my invention is the use of a separate light-transmitting velocity tube for each lamp and closely surrounding the same so as to restrict the cross-sectional area of the path of the cooling water along the length of the lamp and thereby maintain the electrical conductivity of the water between the two ends of the lamp at a value sufficiently low to permit exposure of both lamp leads to the cooling water without interfering with the proper operation of the lamp.

Further objects and advantages of my inven-` tion will appear from the following description of species thereof and from the accompanying drawings in which:

Fig, 1 is a longitudinal section on the line |I of Fig. 2 of a water-cooled multiple mounting arrangement comprising my invention; Figs. 2 and 3 are transverse sections on the lines l2---2 and 3-3 respectively of Fig. 1; Fig. 4 is a longitudinal section on the line 4--4 of Fig. 5 of a modified form of water-cooled multiple mount-A ing arrangement according to my invention;

Figs. 5 and 6 are transverse sectionstaken on the lines 5 5 and 6 6 respectively of Fig. 4; Fig. 7 is a longitudinal section of a watercooled single mounting arrangement according to my invention; Figs. 8 and 9 are transverse sections taken on the lines 8-8 and 9 9 re spectively of Fig. 7; and Fig. 10 is an end view of the device shown in Fig. 7 as indicated by the line Ill-I0 in Fig. 7. v

Referring to the drawings, the device shown in Figs. 1 3 comprises a metal housing or jacket I 0, preferably of brass, having a cylindrical openended hollow central portion l l the Aends of which are closed by flat light-transmitting circular glass windows i2. The said windows are held in water tight relation to the-cylindrical portion 55 Il of the housing by means of retainer rings i3 e -1 which thread`into thecylindrical portion II of the'housing and force the windows I2 against gaskets I4 Ofsuitable material. such as rubber, andthe said gaskets against seating surfaces I5 formed in the cylindrical housing portion II.

One end of the housing or jacket I8 is provided with a hollow base portion I6 ,extending from the side wall -ofthe cylindrical portion II and comprising a circular portion I1, the axis of which extends atright angles to and intersects the axis of thecylindricalportion II, and a flange portion I5 preferably of square coni'iguration. Mounted' within the base portion I6 is a circular insulator member4 I9 of suitable material having relatively high dielectric strength and thermal resistivity, preferably a ceramic material commercially known as Isolantite.

The insulator I9 is provided with a conical bearing portion 28 which is tightly pressed against a correspondingconical seat 2l in the circular housing portion I1 by means of a clamping or vsion 4l is closed by a circular end plate 42, preferably of brass and resti!!! against the flat end surface 43 of the extension 48 and securedthereto by means of screws 44. The outer periphery of the end plate 42 is threaded for engagement with a hollow cup-shaped closure cap 4 preferably of brass, which is screwed onto the said 'end plate and compresses a rubber gasket "4 6 inserted between the said cap and the fiat end surface-43 of the extension 48 to thereby provide a watertight seal between the cap and the jacket I6.

Mounted on the end plate 42 and extending therethrough in coalignment with the three stationary lamp contacts 38, are three resilient lamp contacts 41 each comprising a cylindrical Vplunger 48, preferably of stainless steel and having at its inner end a cylindrical lamp socket portion 49 retainer ring 22 which threads into the ange I8. To insure a water-tight seal between the insulator I9 and the adjacent metal parts, a suitable gasket 23 is inserted between the insulator and the clamping ring 22.

At its inner end, the insulator I9 is provided with a coaxial cylindrical extension 24 of reduced diameter which extends through a circular opening 25 concentrically located in the circular housing portion I1. The said extension 24 and the insulator proper I9 are formed with three closely arranged circular inner and outer chambers 26 and 21 respectively disposed in triangular coaligned formation about the coinciding axes of the cylindrical extension 24 and the insulator proper I9, each of the coaligned chambers 26 and 21 being divided by a transverse partition 28 provided with a 'coaxial'opening 29 of reduced diameter y .extending therethrough. Disposed within each of the'coaligned chambers 26 and 21 is a stationary lamp contact member 38 preferably of brass and comprising a relatively thin circular flange 3| of a diameter such that it will just fit within the inner chamber 26, an inwardly extending lamp socket post 32 of reduced size having a conical seat or socket 33 in its inner end for the reception of the lamp terminal,- as shown in Fig. 1, and an outwardly extending screw-threaded post portion 34 extending through the opening. 29 in the partition 28 into the outer chamber `21. Each of the said lamp contact members 38 is secured within its respective chamber, 26 by means of a nut 35 which threads onto the threaded post portion 34 of the contact member and tightly clamps the flange 3I thereof against a suitable gasket 36 and the latter against the partition 28 to thereby providea water-tight` seal between, the lamp contact member 38 and the insulator I9.

Projecting outwardly from the outer end of the insulator I9 are three brass nipples 31, one for each chamber 26, for connection to watercirculating hoses (not shown). The said nipples are threaded into recesses 38 in the insulator I9 and are arranged in triangular formation about the axis of the insulator and in relatively close relation to their respective inner chambers 26 with which they communicate by means of connecting passageways 39.

y Extending from the side wall of the cylindrical lamp-housing portion II at a point diametrically opposite the base portion I6, is a cylindrical extension 48 having a circular opening 4I extending therethrough. The outer end of said exterislots 54, preferably four in number and extending back from the open `end of the socket. In this manner, the socket is formed of a number of spring fingers which are adapted to tightly grip the lamp terminal. The mounting knob 58 comprises -an outer cylindrical knurled head portion 55, an intermediate cylindrical portion 56 of reduced diameter, and a transversely extending inner wing or locking lug portion 51 the transverse extent of which preferably coincides with the diameter of the knurled head portion 55. The

-mounting knob is provided with a .concentric opening through which the plunger 48 extends, the opening being large enough to .permit easy sliding of the knob on the plunger. The mounting knob is retained on the plunger by means of a head 58 at ,the outer end thereof formed by p eening over the said end after the spring 5I and mounting knob 58 have been assembled on the plunger. v

For the purpose of mounting the three resilient lamp contacts 41 on the end plate 42, the latter is provided with three openings 59 extending I therethrough and disposed in coalignment with the stationary lamp contacts 38. The said openings 59 are of a diameter slightly larger than' that of the reduced intermediate portions 56 of the mounting knobs 58, and are countersunk at their outer ends, as indicated at 68, so as to provide shelves or seats 6I of a thickness such that they will enter thespace between the knurled head portion 55 and the transverse locking lug 51 of the mounting knobs 58. The countersunk portions 68 are of a diameter such as to permit reception therein of the knurled head portion 55 of the' mounting knob 58. The shelf 6I bordering each opening 53 is provided with an elongated diametrical slot 62 of a length and width suiiicient to permit free passage of the locking lug 51 therethrough. The elongated slots '62 are preferably arranged with their lengths at right angles to the radial lines extending from the center of the circular end plate 42 and intersecting the centers of the respective openings 59. To permit free passage of the circulating water through the end plate 42, the diametrical slots 62 are extended, at one endl thereof, a short dis-' tance beyond the countersunk portions 6.0. to thereby provide passage-ways between the hollow interior of the central lamp-housing portion H and the hollow space Within the end closure cap 45 when the resilient contacts 41 are mounted in placeV on the end plate 42.

Mounted within the central portion Il of the jacket I are three high-pressure mercury vapor lamps 63 of the capillary type, such as described and claimed in the aforesaid Bol et al. Patent No. 2,094,694, and comprising a cylindrical quartz bulb 64 having a cylindrical metal terminal 65 at each as to cause a slight Vcompression of the spring 5I on the resilient contact 41 when a lamp 63 is inserted .between such sockets. In.this manner a good electrical connection is insured at all times :between the socket 33 and the co-operatin'g lamp terminal, as well as between the opposite lamp terminal and the jacket itself through the socket 49, plunger and spring 48 and 5| respectively and the mounting knob 50.

To insert the lamps 63 in the jacket I0, one end of a lamp is inserted in the socket 49 of one of the resilient contacts 41, the spring fingers of the socket 49 securely holding the lamp therein. The lamp, with its attached contact 41, is then introduced into the jacket through one of the openings 53 in the end plate 42 until the innermost end orf the lamp is received in and engages the conical seat 33 in the corresponding stationary contact 36 at the insulated end of the jacket l0. Thereafter,

the mounting knob on the resilient contact 41 is further moved inwardly, against the resistance of spring 5|, until the locking lug 51 enters the elongated slot 62 in the end plate 42, after which the knob 50 is turned one way or the other so as to lock the lug 51 against the underside of the shelves 6l,asshowninFig.3..

Placed concentrically around each of the lamps 63 is a velocity tube 66 of suitable light transmitting material, such as glass. The said tubes 66 extend into the inner chambers 26 inthe insulator block I9 and t closely therewithin so as to be rigidly supported from' the insulator block. In addition, the close t of the tubes 66 in the 'chambers 26 compels the circulating water entering and` leaving the jacket I0 through the nipples 31 to flow through the said tubes 66. The inner diameter of the tubes 66 is such as to -provide asmall radial clearance from the lamp of about 1 mm. or thereabouts through which the water must flow. Because of this restricted ycross-section of the circulating water, the electrical conductivity thereof between the exposed lamp terminals 65 is kept at a relatively low value, sufficiently low to lprevent any material interference with the proper operation of the lamp. Thus I have found that Where a 1000 watt lamp is enclosed by a velocity of .previous water-cooling arrangements, thus producing a small, compact, high-intensity light source, such as required for many applications,

including search-lights, airport beacons, and

photo-engraving and photo-lithography.

The velocity tubes 66 further serve to impart a relatively high velocity to the cooling water. Because of the restricted annular cross-section of the cooling water, more than ample water velocity is attained to prevent the' undesirable formation of steam bubbles with a water flow of about three liters per minute. Thus, with an annular passage about one millimeter wide around the lamp, a flow o fapproximately three liters per minrute gives ample vvelocity and a temperature rise less than 3 C. Thev use of the velocity tubes 66 thus has made it possible to reduce the amount of cooling water over that heretofore necessary to effectively cool the lamps, because it is not the. amount of water, but merely the surface velocity over the lamp that matters. The criterion for proper cooling is that the speed of flow should be great enough to prevent the formation of any steam bubbles.

In accordance with the invention described and l claimed -in copending U. S. application Seriaf 174,860, Van Alphen et al., filed November 16, 3'?

and assigned to the assignee of the present invention, which issued as Patent No. 2,223,470, Dec. 3, 1940, the velocity tubes 66 are made of an ultraviolet absorbing material, preferably a lead-bearing hard glass such as that commercially known as Nonex. Asa consequence, the velocity-tubes 66 additionally serve as ultra-violet iilters for, absorbing the ultra-violet radiations from the 1am-ps 63. In this manner, the absorption by each lamp of the ultra-violet radiations from the adjacent lamps is entirelyprevented. This is an important consideration, inasmuch as such an absorption by the lamps themselves of the ultraviolet radiations of the adjacent lamps would cause an increase in the pressure and temperature of each lamp, with consequent short life thereof.

To l.permit expulsion of trapped air within the j'aicket l 0 when it is filled with cooling water and during the circulation of the same,"the jacket is provided with a pair of valves comprising ca p screws 61 threaded into diametrically opposite -holes 68 in the .cylindrical wall of the central lamp-housing portion Il of the jacket. Each of the cap screws 61 is provided with a concentric boss 69 on the underside orf the screw head which compresses a rubber gasket 10 `fitting in a recess 1| in the jacket so as to provide a water-tight seal when the valve is screwed down tight. The

threaded stud portion 12 of the valve is provided with a longitudinal bore 13 and a transverse pas- 'sage 14 which connects the interior of the jacket tube 66 providing an annular space of about 1 with the atmosphere when the valve is unscrewed, thus permitting thef escape ofany trapped air. Inasmuch as the lamps 63 are adapted to be operated in a horizontal position, the valves 61 .are so located in the jacket portion II lthat one or the other will-always be at the top o f the device at the point where trapped air will collect. Thus, as" shown in Fig. 1, the valves 61 are located diametrically opposite one another and in a line normal to the longitudinal axis of the lamps 63. l In operation, one of -the circulating warteA npples 31 is connected to an intake hose (not shown), While the other two nipples are Connected to outlet hoses (not shown). Electrical connections to the lamps 63 are made at one end to the threaded studs 34 on the stationary. contacts 30, and at the other end to the lcasing of` the jacket itself which is electrically connected, through the end plate 92, to the resilient lamp contacts 91. After the flow of water has begun through the jacket, the electrical circuit through the lamps 99 may then be closed so as to start the operation thereof. Y A

An important feature of the arrangement described above is the easy interchangeability of the individual lamps. Thus, when any lamp fails, it is merely necessary to unscrew the closure cap 95 and remove the defective lamp from the Jacket by grasping the knurled head 65 of the resilient contact 91 in which the defective lamp is held, turning the same until the transverse locking bar 51 comes opposite the elongated slot 92 in the end plate 92, and then withdrawing the said contact 91 together with the attached defective lamp which is securely held in the socekt 99 of the contact by the spring fingers thereof. A new lamp may then be inserted in the socket 91 and introduced into the jacket as described hereinbefore, the resilient contact 95 being again locked inposition in the end' plate 92 and the closure cap 95 replaced.

The modification illustrated in Figs. 3, 4 and 9 differs from the form shown in Figs. 1, 2 and 3 mainly in that the metal jacket I9 is replaced by a heavy cylindrical light-transmitting glass tube 15 which surrounds the three lamps 69, the ends of the tube being clamped between a brass end plate 19 and the insulator I9, the latter be-I ing supported in a second brass end plate 11.

of the glass tube 95, and the end members 99 and 99 to provide a water-tight seal therebetween.

Centrally mounted within the insulator 99 is a cylindrical brass intake tube 99 having an outwardly extending flange 99 at its inner end which is clamped between gasket 99 and the insulator 99 to thereby securethe intake tube in place in the insulator and to provide a water-tightconnection between the said intake tube and the glass tube 92 surrounding the lamp.

Secured within and extending inwardly from the intake tube 99 is a resilient lamp contact 9| comprising a brassplunger 92 having at its in-A nermost end a head 99 provided with a conical seat or socket 99 in which the lamp terminal 99 is received. Said contact 9| further comprises a brass sleeve 95 secured to the intake tube 99 andthrough which the plunger-92 slidably extends, and a stainless steel helical compression i spring 96 concentrically mounted on the plunger The two brass end plates 16 and 11 are held together by retaining bolts 19 locatedl exteriorly of the glass tube 15, and rubber gaskets 19 are inserted between the end of the glass tube and the end plate 16, and between the opposite end of the glass tube and the insulator |9, to thereby provide awater-tight seal therebetween. The central portion of enel plate 16 is of the same construction as the central portion of end plate 92 in Figs. 1-3. The said plate 16 is provided with a lcentrally located outwardly projecting annular flange 99 threaded on its outer periphery for engagement with a closure cap 9| similar to the cap 95 in the first form of the invention described hereinabove.

Figs. 7, 8 and 9 disclose a single-lamp watercooled unit according to the invention which is designed for those applications where a large volume of ultra-violet energy of all wave-lengths is required, particularly from avsource having high concentration. This modification of the invention is similar to that disclosed in Figs. 4-6

in that it comprises a glass tube 92 surrounding.

the lamp 99 and clamped between two end members comprising a brass en d plate 93 and an insulator end member 99 preferably oflinen Textolite." the glass tube 92, in addition to serving as the `iacket for the vcirculating water, also serves as the velocity tube for imparting high velocity to However, it differs mainly in that` 99 provide ample passageways for the flow of the circulating water'as it passes over the lamp.

For this purpose, the glass tube 92 is provided with a central portion 95 of reduced diameter which closely surrounds, and extends along the greater part of the length of the lamp 93. This constricted portion 95 thus serves as the velocity tube in the same manner as the velocity tubes 99 in the previous forms of the invention.

The brass end plate 99 and the insulator 99 are held together by retaining bolts 99 which are insulated from the plate 93 and spaced from the insulator 99 by suitable rubber bushings 91. Rubber gaskets 99 are inserted between the ends 92 between the head 99 thereof and the sleeve 99. At its outer end, the plunger 92 is provided with a transversely extending stop pin 91 which abuts against the outer end of sleeve 95-to thereby lock the plunger within the sleeve. As shown particularly in Fig. 10, the sleeve |9 is made from a bar of rectangular cross-section the corners of which are ground flat, as indicated at 99, so as to flt tightly against the inner wall of the intake tube 99. To insure that the sleeve is positively secured to the intake tube 99, the corners 99 of the sleeve are preferably soldered to the said tube. The spaces 99 between the sides of the sleeve 95 and the surrounding intake tube the cooling water into the glass tube 95 surrounding the lamp, the narrower sides |99 preferably being formed concave, as shown in Fig. l0. to increase the cross-section of the spaces between such sides and the intake tube.

Electrical connection to the resilient contact 9| is made through a brass connector ring |9| secured to the sleeve 95 by set screws |92 (Fig. l0) and a brass terminal connector |93 threaded into said connector ring. To prevent any possibility of electrical shock, the connector ring is enclosed in an insulating cap |99, and the terminal connector encased in an insulating bushing |95. 'I'he cap |99 is secured to the connector ring |9|, and the bushing |95 to the cap |99, by means of the threaded terminal conductor |99. The exposed portion of the intake tube 99 extending out` beyondthe cap |99 is enclosed by the rubber water-inlet tube (not shown) dur-v ing operation of the device, thus completing Vthe insulation of all the metal parts at the intake end of the device.

The brass end plate 99 at the outlet end of the device is provided with a brass outlet tube |96 extending outwardly therefrom and secured thereto by a knurled brass collar |91 which threads into a centrally located recess |99 in the flange a stationary lamp contact ||9 is mounted.

the outlet tube |99 and a good.contact is provided The said contact H3 comprises a brass stem lll having a longitudinally slotted socket portion at its inner end and a stud portion |I6 of reduced diameter extending outwardly from the socket portion H5. Secured on said stud portion ||6 by a press t and resting against the socket portion ||5 is a perforatedl socket mounting disc |l1. The said disc seats on the annular ange 'I I2 in the reduced portion of recess'l08, and is provided with a plurality of circular openings ||8, preferably four in number and arranged in a circle about the socket ||5. The said openings provide passageways between the glass tube 82 and the outlet tube |06 through which the cooling water or liquid can of the stationary contact ||3 1s provided with Aa transverse locking bar or lug ||9 which is spaced inwardly from the disc ||1 a distance slightly greater than the thickness of the annular ange H2 so that the latter can .enter the space between the said lug as to securely fasten the latter to the end plate and complete the assembly.

To insure a good electrical connection at all times between the stationary lamp contact ||3 and the brass end plate 83, the inner end of the outlet tube |06 is provided with a truncated conical helical compression spring |2| of stainless steel extending inwardly from the said tube |06 and engaging the disc of the stationary contact H3. At its outer end, the spring |2| is proclosed-wound therein. When the collar |01 place in the end plate 83 so as to secure the outlet tube |06 thereto, the conical spring- |2| engages the disc ||1 and is compressed by the'inward movement of the outlet tube |06. The compressive force of spring |2| being greater than that of the spring 96 in the resilient contact 9|, the disc is forced against the annular flange l2 with considerable pressure. The result is that betweenpthe stationary contact I3 and the brass end plate 83 at all times.

Inasmuch as the modication illustrated in Figs. 7 to 10 is for a single lamp only; there is no is screwed into retaining bolts 86, there is no o! absorption by adjacent glass jacket or tube l2 a material which will transmit any desired radiations, f or instance quartz, which will transmit the ultra-violet radiations of the lamp 63. Thus, the device may be especially adapted for use where a large volume of ultra-violet energy of all wave-lengths is required.

Because all mechanical strain is taken by the need for absorbing the ultra-,violet radiations the lamp to prevent their jacket 82' being cracked even formed into a strained condition by the adverse eiect thereon of the ultra-violetv radiations oi' the lamp. y

What I claim as new and desire to secure by Letters Patent of the United States is:

2. A liquid-cooled mounting device for a high intensity tubular electric lamp having wopposite ena terminals, said device comprising a Jacket at least a portion o1 which 1s light-transmitting and column to a harmless'value.

3. A liquid-cooled mounting device for a pludanger of the glass though it be transs cooling liquid a plurality o! light-transmittins velocity tubes.

one for each o! said lamps, closely surrounding said lamps for the greater part of their lengths and arranged to segregate thel cooling liquid at the Vintake end of each of said tubes from the cooling liquid at the outlet end of each of said tubes, said velocity tuhes sewing to conilne the cross-section ot at least the greater part of the column between the opposite ends of said lamps.l to an area of sufllciently small cross-section to lower the electrical conductivity o! the said liquid `column to a harmless value. .4. A liquid-cooled mounting device for a high intensity tubular electric lamp havingopposite end terminals, said device comprising 'a Jacket having an intake and an outlet connection for the cooling liquidI a pair o! opposed lamp sockets within said Jacket for supporting the lamp with the end terminals thereotboth in electrical contact with the cooling liquid, and velocity tube means closely surrounding the lamp tor confining the cross section of the cooling liquid path between the opposite ends of the lamp to. an area of'suillciently small cross-section to lower the electrical conductivity oi the said liquid column to a harmless value.

5. A liquid-cooledmounting device for a high said end plate insulator and disposed within said Jacket member. and a removable lamp socket mounted on inapositionoppositethe saidflxed socket, said removable socketbeing provided with means for positively grippinl the lamp so as. to form a single unit therewith during the insertion of the said lamp and removable socket into said device and their removal therefrom.

6.. A liquid-cooling mounting for tubular lelectric lamps having c `t supply terminals at their ends comprising a jacket having openings at opposite ends thereof, an insulating plug member lling theopening at one end of said Jacket, said plug member having a plurality o! bores in alignment with the opening at the o! the `jacket. a contact and support member in lamp may be withdrawn,

arranged to grip their intensity tubular electric lamp having opposite end'terminals, said device comprising an outer jacket member open at its opposite ends, an irisulator secured to and closing the opening at one end of said jacket member, a passageway for the flow of a cooling liquid therethrough into said jacket member, a metal end plate secured to the other end of said jacket member, a fixed lamp socket mounted on said said' insulator having each or said bores extending t6 the exterior of said plug, a support and cover plate member over the opening at the said opposite end of the Jacket, a plurality of contact and support members each in alignment with one of said first-mentioned contact and support members to hold a lamp' therebetween, means on each of said second-mentioned contact and v engaged in an opening in said cover plate member through which the associated contact member and said second-mentioned contact members being associated lamps to effect such withdrawal, a cap member covering said cover plate and associated contact and support tending from each of the bores in said plug member to closely surround the associated lamp, and a passagey for liquid extending through said plug member from each ot said bores.

EDWARD B. NOEL.

Opposite end support members removably members, a velocity tube ex- 

